How to do URL matching regex for routing framework? - php

Question

I already have a routing method that matches this pattern:
/hello/:name
that set name to be a dynamic path, I want to know how to make it:
/hello/{name}
with the same regex. How to add optional trailing slash to it, like this?
/hello/:name(/)
or
/hello/{name}(/)
This is the regex I use for /hello/:name
#^/hello/([a-zA-Z0-9\-\_]+)$#D
The regex is auto generated from PHP class
private function getRegex($pattern){
$patternAsRegex = "#^" . preg_replace('/\\\:[a-zA-Z0-9\_\-]+/', '([a-zA-Z0-9\-\_]+)', preg_quote($pattern)) . "$#D";
return $patternAsRegex;
}
If the route is /hello/:name(/) I want it to make the match with optional thing else continue normal

Answer 1

This will create a regular expression for the $pattern route with both :name and {name} parameters, as well as the optional slash. As a bonus, it will also add a ?<name> to make the parameter easier to handle down the line.
For example, a route pattern of /hello/:name(/) will get the regular expression #^/hello/(?<name>[a-zA-Z0-9\_\-]+)/?$#D. When matched with a URL, like preg_match( <regex above>, '/hello/sarah', $matches) that would give you $matches['name'] == 'sarah'.
There are some tests to be found below the actual function.
function getRegex($pattern){
if (preg_match('/[^-:\/_{}()a-zA-Z\d]/', $pattern))
return false; // Invalid pattern
// Turn "(/)" into "/?"
$pattern = preg_replace('#\(/\)#', '/?', $pattern);
// Create capture group for ":parameter"
$allowedParamChars = '[a-zA-Z0-9\_\-]+';
$pattern = preg_replace(
'/:(' . $allowedParamChars . ')/', # Replace ":parameter"
'(?<$1>' . $allowedParamChars . ')', # with "(?<parameter>[a-zA-Z0-9\_\-]+)"
$pattern
);
// Create capture group for '{parameter}'
$pattern = preg_replace(
'/{('. $allowedParamChars .')}/', # Replace "{parameter}"
'(?<$1>' . $allowedParamChars . ')', # with "(?<parameter>[a-zA-Z0-9\_\-]+)"
$pattern
);
// Add start and end matching
$patternAsRegex = "#^" . $pattern . "$#D";
return $patternAsRegex;
}
// Test it
$testCases = [
[
'route' => '/hello/:name',
'url' => '/hello/sarah',
'expectedParam' => ['name' => 'sarah'],
],
[
'route' => '/bye/:name(/)',
'url' => '/bye/stella/',
'expectedParam' => ['name' => 'stella'],
],
[
'route' => '/find/{what}(/)',
'url' => '/find/cat',
'expectedParam' => ['what' => 'cat'],
],
[
'route' => '/pay/:when',
'url' => '/pay/later',
'expectedParam' => ['when' => 'later'],
],
];
printf('%-5s %-16s %-39s %-14s %s' . PHP_EOL, 'RES', 'ROUTE', 'PATTERN', 'URL', 'PARAMS');
echo str_repeat('-', 91), PHP_EOL;
foreach ($testCases as $test) {
// Make regexp from route
$patternAsRegex = getRegex($test['route']);
if ($ok = !!$patternAsRegex) {
// We've got a regex, let's parse a URL
if ($ok = preg_match($patternAsRegex, $test['url'], $matches)) {
// Get elements with string keys from matches
$params = array_intersect_key(
$matches,
array_flip(array_filter(array_keys($matches), 'is_string'))
);
// Did we get the expected parameter?
$ok = $params == $test['expectedParam'];
// Turn parameter array into string
list ($key, $value) = each($params);
$params = "$key = $value";
}
}
// Show result of regex generation
printf('%-5s %-16s %-39s %-14s %s' . PHP_EOL,
$ok ? 'PASS' : 'FAIL',
$test['route'], $patternAsRegex,
$test['url'], $params
);
}
Output:
RES ROUTE PATTERN URL PARAMS
-------------------------------------------------------------------------------------------
PASS /hello/:name #^/hello/(?<name>[a-zA-Z0-9\_\-]+)$#D /hello/sarah name = sarah
PASS /bye/:name(/) #^/bye/(?<name>[a-zA-Z0-9\_\-]+)/?$#D /bye/stella/ name = stella
PASS /find/{what}(/) #^/find/(?<what>[a-zA-Z0-9\_\-]+)/?$#D /find/cat what = cat
PASS /pay/:when #^/pay/(?<when>[a-zA-Z0-9\_\-]+)$#D /pay/later when = later

Answer 2

Simply replace your regex with this for optional / :
#^/hello/([a-zA-Z0-9-_]+)/?$#